Pneumatic swab



PNEUMATI C SWAB Feb. 16, 1932.

Patented Feb. 16, v1932 STATES PATENT OFFIC.

QLD W. FLETHER, F HOUSTON, TEXAS, ASSIGNOR T0 HUGHES TOOL COMPANY,

OF HOUSTGN, TEXAS, A CORPORATION 0F TEXAS PNEUMATIG SWAB Application filed Detober 27, 1924. Serial No. 7453398.

My invention relates to fluid pressure operated swabs, and is particularly adapted for application to deep well operations in raising oil or water to the surface.

ln pumping deep oil and water wells by' ing and repair.

lt is an object of my invention to provide a swab, which may be operated by pressure ot air or gas, whereby the duid may be raised 'from the well in such manner as to avoid the usual ditliculties with sand and other foreign matter.

llt is also an object to elevate liquid in such manner as to draw sand and other ac cuniulations along with the oil so that the well will not become clogged. lt is desired to torni a swab for pumping wells which will be cheap and economical to construct, which may be operated continuously for long periods of time without repair, and which may be repaired when necessary without the necessity of withdrawing the, working parts trom the well.

Referring to the drawing herewith wherein a preferred embodiment of the invention is disclosed, Fig. 1 is a central longitudinal section through a well casing and tube wherein my invention is employed; F ig. 2 is a similar View showing the operatingparts in different position; Figs. 3 and 4 are longitudinal sectional views of the swab plunger, in lowered and raised positions respectively. Like numerals of reference are employed to designate like parts in all the views.

ln carrying out my invention, I contem plato employing a casing in the well hole which will preferably be coupled together tightly at the joints and will extend down to the bottom ot the well. At the upper end of the casing, ll secure a casing head 2 having ln some cases the sand will clogl head 21 of the valv-e stem and hold it in low one or more lateral pipes 3 connected therewith through which air or gas under pressure may be pumped. At the upper end of the casing head is formed a stuling box 4 in which a gland 5 is forced downwardly upon the packing 6 by means of clamping bolts 7 of ordinary construction.

A well tube 8 is slidable within the stuliing box so that it may be raised or lowered in the well to adjust the same relative to the oil level therein. At the lower end of the tubing a coupling 9 is provided connecting the well tube with an inlet pipe or strainer 10. Above this coupling 9, the well tube 8 is perforated at 11 for a short distance to allow the entrance of fluid to the tube. At the upper end of the well tubeis a nipple 12 closed at its upper end by a cap 13, and having a lateral outlet pipe 111' therein adjacent the lower end olf the nipple. The cap 13 has a central, down wardly projecting stop pin 32 thereon to engage withthe swab valve as will presently appean A swab piston 15 is adapted (to fit closely Y within the well tube so as to slide freely therein and assist in raising the liquid from the well. The said swab piston is cylindrical in form, having the lower end open. At the upper end, the walls of the piston are turned inwardly to forma tapered seat 17 to receive 8v the head 18 of a Valve, the stem 19 of which extends downwardly within the piston, and is slidable within a guide 20 intermediate the ends of the piston. The head 21 on the lower end of the stem 19 serves to engage with latching dogs 16 pivotally mounted on downward ly extending ears 25. The upper ends of the said dogs are curved inwardly and each has a shoulder 26 adapted to engage above the ered position. A spring 27 upon thevalve stem bears at its upper end against the lower tace of the valve 18, and at its lower end against the guide 20,` thus serving to hold the valve normally seated. The lower ends of the dogs are held resiliently apart by a spring 28 and said ends are curved to provide cam faces 29 by which they may be forced inwardly by contact with the inwardly beveled face of a supporting shoe 30.

The shoe 30 is a cylindrical tubular member having a radial flan e 31 thereon forming a seat for the swab p unger when in low-- ered Qsi'tion. The upperend telescopes lfreely wlthin the swab body to contact with the latching dogs 16, as shown in 3. The shoe 30 is itself` resiliently supported upon a spring 22 which in turn is supported upon the inner iiange 23 of the coupling 9. The swab plunger is thus normally positioned immcliately 'above the openings 11 in the well tu a In the o eration of this device the tubing is lowered ownwardly through the stuing box into the well until the lower .end of the well tube is at a suitable distance below the oil level indicated at 24. The piston is at that time supported upon the spring 22 in the position indicated in Fig. 1. Air or gas under pressure is then pumped into the casing through the pipe 3, and as the pressure is i lgradually increased the level 24 of the oil will v gradually forced downwardly within the casing and when the level has passed below the openings 11 in the well tube, the air will then enter the tube and be exerted upwardly upon the swab piston 15. The air will bubble lso in below the valve in the swab and will accumulate of liqui When in normal position, supported upon thesho'e 30, the dogs 16 will be withdrawn', allowin the spring 27 to hold thev valve seated. Thefaction of the air pressure will then be to force the piston with its load of oil upwardly. The pressure of air below and that of the fluid above the valve will be approximately equal, and the -increased area of the lower face, together with the force of the spring 27 willhold the valve seated. The load of oil will thus be raised to the'surface by the essure of air being pumped inwardly r vthrough the pipe 3, and the load of oil will finall be discharged through the outlet pipe 14.l he valve will then pass upwardly into nipple 12 as shown in Fig. 2. 'An upwardly extending pin 33 on the valve will then contact witlr the stop pin 32 on the cap 13,`and force the valve downwardly so that the head 21 will beforcedpast the latching dogs 16, which .will engage above the head and hold the valve is its open position. y

a The air behind the valve will exhaust outwardly through the pipe 14 followilg the oil, and the pressure within the tube an the casing will be relieved suiciently to allow the oil to again rise in the casing closing the openings 11 and shutting oi the exhaust from the casing. The valve will then drop downwardly into its normal position, supported resiliently upon the spring 22. As the swab piston strikes the upper end of thesupportmg shoe 30, the lower ends 29 of the dogs will strike with some force against the beveled upper face'of the shoe, throwing them inf pressure to raise the swab and itsload of the structure. I The swab piston is entirely un-connected with any apparatus at the surface. It may 't somewhat freely within the tube 8, which does not need to be specially ground or machined, and may thus be of more economical 'construction. There will be a film of fluid between the swab plunger and the tube, and the fact that the Huid pressure below' and above the piston will be approximately equal while the load is being ifted, will tend to overcome any slight tendency of the liquid or air to be forced by the .lunger' body. The supporting device, inclu ng the spring 22 and the shoe 30 will serve to prevent any shock to the apparatus due to the dropping of the plunger rom the upper end of the well to the lower end. It will be understood that the discharge of the air following the discharge of the oil will relieve the pressure more completely within the tube than within the casing, having the result that the fluid will vimmediately rise to a higher position within the tube than in the casin ,.as shown in Fi ...2. The piston will drop t rough this liqui readily, however, due to the fact that the valve will be held lo'cked in open position until the plunger engages with its supporting shoe 30.

The action of this device will be practically automatic, it being only necessary to operate the air compressor so as to build u the required pressure within the casin ollowing each discharge of oil. It will a so be noted that the discharge of comparatively large quantities of oil in this manner will allow an inrush 'of oil .and sand from the lower end of the well upwardly into the tube, and that this load of liquid with its impurities will be raised to the surface without the usual tendency of the sand and sediment to get between theplunger andthe tube, due to the fact that the pressures below the swab are approximately verplel to the pressure above. It will therefore possible to keep the bottom of the well clear of sand, and little wear upon the plunger and the tubing will result. The apparatus will thus last for a long period of timewithout repair, but if re air to the plunger becomes necessary, itmay removed and repaired by catching the plunger at the upward end of its stroke, thus making it unnecessary to remove the pipe from the w'ell.

Other obiects and advantages of the invention will be apparent to those skilled in the art Without further description.

I What I claim as new` and desire to protect by Letters Patent, is: 'A l. A swab of the character described, comtit prising a well casing, a casing head thereon, an inlet pipe in said casing head :tor air under pressure, a stuffing box at the upper end of said easing head, a well tube slidable in said stuing box, a nipple closing the upper end oi' said tube, an outlet pipe at the lower end of said nipple, a coupling adjacent the lower end olf' said tube, said tube being perforated above said coupling, and a swab piston supported resiliently above said pertorations, said piston having a normally closed downwardly opening valve therein and means wherby said valve is opened at the upper end of the travel ot the swab.

f2. A swab of the character described, com prising -a well casing, a casing head thereon, an inlet pipe in said casing head for air under pressure, a stuiing box at the upper end of said casing head, a well tube in said stuffing boa, an outlet pipe on said tube, said tube hav ing openings therein adjacent the lower end, and a swab-piston in said tube above said openings, said piston having a downwardly opening valve therein, means to hold said valve normally closed, and means at the upper end oi said tube to open said valve.

3. A pneumatic well swab, comprising a casing closed at the upper end, except for a compressed air inlet pipe, a tube slidable in said casing, a piston supported above the lower end of said tube, said tube being perfo! rated below said piston, a nipple at the upper end of said tube, said nipple having a discharge pipe thereon at its lower end, whereby air pressure in said casing may raise said piston above said discharge pipe in the manner described, a valve closing a passage through said piston, and means to open said valve at the upper end of said tube.

at. lin a pneumatic well swab, a casing, a casing head thereon.. a lateral pipe thereon, a 'well tube slidable fluid tight in said casing head, said tube having an opening atjthe lower end, a piston'in said tube above said opening, said piston having a downwardly opening valve therein, a nipple at the upper end ot said casing to receive said piston, an outlet pipe'in said nipple at its lower end and means in said nipple to open said valve.

5. lin 'a pneumatic well swab, a casing, a well tube therein extending from the lower end ot the well to the surface and having an opening therein at the lower end, a piston above said opening, means to allow pneumatic pressure to be exerted below said piston to move it to the upper end of said tube, a valve in said piston adapted to be closed during the upward movement of said piston means at the upper end ot said tube to open said valve, and means to allow a discharge of fluidfrom said tube.

u. pneumatic swab comprising a well casing, a casing head having an air inlet pipe ltherein, a well tube slidable through a stuffing box in said casing head, a piston at the lower end of said well tube, said tube .being perforated below said piston, a downwardly opening valve in said piston, means at the lower end of said tube to close said valve and means at the upper end of said tube to open said valve and releasable means to hold said valve in open position.

7. A pneumatic swab for raising liquid from wells comprising a casing, a tubing therein, a detached piston in said tubing, a downwardly opening valve in said piston adapted to be held closed on movement of the piston upwardly and positive means to hold said valve open on its movement downwardly, and means to allow fluid pressure to be exerted below said piston to move it upwardly for the purpose described.

8. A pneumatic swab for raising liquid from wells comprising a casing, a tubing therein, adetached piston in said tubing, a valve in said piston, means to hold said valve normally seated, means automatically operated to latch said valve in open position at the upper end of said tubing, whereby it may drop freely, and means to allow fluid pressure to be exerted upon said piston, to raise it to the surface.

9. A process of raising liquid from wells having therein a casing and a tubing, comprising continuously compressing gas within the space between the casing and tubing until the liquid level is lowered to allow entrance of gas at the lower end of said tubing separating said liquid and gas and raising a charge ot liquidin said tubing above the compressed gas to discharge it at the surface and then allowing the gas to exhaust whereby the liquid level may rise and the operation be repeated.

10. ln a pump, the combination of a vertically disposed casing, a swab movable in thecasing, means for supplyin a pressure medium near the lower` part o `the casing, for lifting the' swab, a valve carried by the swab, and latch means for holding the valve in open position.

11. In a pump, the combination of a vertically disposed casing, a swab movable in the casing, means for supplying a pressure medium near the lower part of the casing for lifting the swab, a spring for moving the valve to the closed position, and latch means for holding the valve in the open posit-ion..y

12. In a pump, the combination oi' a vertically disposed casing, a swab movable in the casing, means for supplying a pressure medium near the lower part of the casing, for lifting the swab, a valve carried by the swab, mounted so that downward movement of the valve opens it, the valve when open allowing the pressure medium to pass through the swab, thus permitting the swab to move down. latch means for holding tbe valve open, and spring means for moving the valve to the closed position.

lifting the 13. In a pump the combination of a vertically disposed casing, a swab movable in the casing, means for supplying a pressure medium near the lower end of the casing, for swab, a valve carried by the swab,

downward movement of the valve moving it to the open position, a spring for moving the valve'upward to closed position, latch means carried by the swab for holding the 4valve open, contact means at the upper end of the path of travel for controlling the opening of the valve, and contact means at the lower end of the path of travel of the swab for releasing the latch means for allowing the spring to close the valve.

14. A pneumatic well swab, including a casing closed at the upper end except for a p compressed air inlet p1 e, a tube in said casing, a piston4 supporte above the lower end of said tube, said tube being perforated below said piston, a nipple at the upper end of said tube, said nipple having a dischar e opening thereon at its lower end, whereby a1r pressure in said casing may raise said piston above said discharge opening, said piston having a valve therein adapted to automatically open at the upper end of its travel and to automatically close at the lower end of its travel.

15. A pump assembly includinfg a well casing, a tube within and spaced rom said casing whereby a passage is formed between them, a swab freely movable in said tube, and means to feed pressure fluid continuously thru said'passage at a level below said swab to elevate said swab and its load.

16. In a pump assembly, a pair of concentric pipes, means to force pressure fluid into the annular space lbetween said pipes, a freely movable swab in the inner pipe, and means arranged to permit said pressure fluid to elevate said swab.

17. In a pump, a pair of concentric'pipes arranged to provide a reversed passage from the top to the bottom of a well, a swab freely movable in one of said pipes, and means to feed pressure fluid to said passage to operate said swab, a nipple at the upper end of the inner of said pipes to receive said swab, said nipple having an outlet at its lower end.

18. A pump comprising a casing, a tube within 'said casing, aswab free to travel the length of said tube,and means to feed pressure fluid into said casing to operate said swab. t

19. In a pump, a casing, a tube therein, a swab adapted to freely travel the length of said tube, means to feed pressure fluid to the space between .said tube and casing, and additional neans whereby the pressure fluid may flow to a point below said swab when said swab is at they base of said tube.

20. In a pneumatic ,pump, a casing, a tube therein extending from -the surface to the desired depth, a swab adapted to freely travel a the length of said tube, and means carried by said swab to control the flow offluid there-y from the surface into the fluid being pumpe land having normally open ports therein adjacent the lower end, a swab adapted to travel freely in said tube, a nip le atv the up-V er end of said tube having a ischarge outlet below the upper end thereof, means to deliver pressure fluid through said portsjbelow said swab, saidA pass said outlet into said nipple to permit the discharge of pressure fluid below said swab.

23. In a well having a casing and an eduction tube therein, the process of raising liq-. uid from said well comprising exerting a fluid pressure in said casing to force the level of liquid in the well downward to allow inlet of said fluid to said tube adjacent its lower end, separating said fluid from the load of liquid above it, discharging said load from said tube.y

24. A method of raising liquid from wells pressure fluid into the well casing, allowing swab being adapted to y lifting said load to the surface and" this constant flow to accumulate in the'casing until the static head of liquidA in the well is depressed to a predetermined point, forcing said pressure fluid to enter said tube below the liquid thereon, lifting said liquid in a mass through the pressure of saidfluid by preventing the mixing of said fluid and liquid, and then permitting the liquid and accumulated pressure fluid to esca 25. A method of raising liquid from wells including trapping a predetermined weight of liquid above a plunger in a pipe, forcing pressure fluid continuousl into said well to exert pressure beneath said' plunger until it rises with the trapped liquid to the upper end of the well, allowing the trapped liquid and .fluid to discharge in succession from the die liquid and fluid at the surface, and allowing the plunger to fall to the starting posinon.

QT. A method of raising liquid including trapping a static head of the liquid above :i freely movable plunger in a pipe aceumubiting pressure fluid beneath the plunger and 'forcing said plunger and liquid to the suri'nee, discharging the liquid from above and the pressure fluid from below the plunger, opening a passage in the plunger so that it may sink to the bottom of the Well and closing said passage after another load of the liquid has been trapped.

2S. A pneumatic swabbing device including a easing, an eduotion tube therein, said eduetion tube having its upper end closed and an opening spaced slightly below said upper mul to provide a. nipple above the said opening. a swab lunfrer fre'el sldable from i P e Y he lower end of said tubing to the upper end iereof, and means to admit pressure fluid w die tube below said swab, to force said web upwardly past said opening into said nipple.

29. lir combination with a Well, a fluid operated pump including a pump barrel which extends from the surface to the pumping depth, a freely traveling plunger in said barrel adapted to move from the bottom t0 the lop ol'" said barrel, and automatically operable means to control the movement of said plunger.

ln testimony whereof, I hereunto allx my signature this the 23rd day of ctober, A. D.

HAROLD W. FLETCH'ER. 

